Fig. 18 is a Gros de Tours with two picks on four harness straight through.

Fig. 19 illustrates this weave with three picks drawn end and end on two sections of four shafts each.

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[Page 20] SERGE or TWILL WEAVES

While the taffeta weave produces either an entirely smooth fabric, or one with a distinct transverse rib as in gros-grain, the twill weave forms diagonal lines on the cloth, running either from left to right or from right to left.

To make a twill, not less than three ends and three picks are required, of which each thread floats over two of the other system and interlaces with the third.  The rotation of the interlacing is always consecutive, that is it moves with each succeeding pick one thread to the right (or to the left if the lines are to run in that direction).  If warp and filling have the same texture, that is the same number of threads in a given space, the twill lines will form an angle of 45 deg.; if the warp stands closer than the filling, the incline will be steeper, and in the opposite case the angle will approach more the horizontal.

The weaves can be expressed in numbers, for instance:  the 3-end twill warp effect would be marked 2-1, which indicates that each warp-thread goes over two and under one pick.

Twill weaves are called evensided when the arrangement of “warp up” and “filling up” are evenly balanced, and unevensided if either warp or filling predominate on the face of the fabric; the latter class is therefore subdivided in Warp effects and Filling effects.

In the following a number of serge weaves are illustrated, the French designations being added in some cases, as they are still extensively used in the trade.

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FILLING EFFECTS

Satin de Lyon, 2-1.

On 6 harness straight through.

[Illustration:  Fig. 20]

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Levantine, 3-1

On 8 shafts skip draw.

[Illustration:  Fig. 21]

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[Page 22] Polonaise, 5-1

On 12 harness skip draw.

[Illustration:  Fig. 22]

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Serge grosse cote, 7-1

On 8 shafts straight through.

[Illustration:  Fig. 23]

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[Page 23] Serge remaine, 6-2

On 8 shafts skip draw.

[Illustration:  Fig. 24]

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Serge, 5-1, 1-1.

On 8 shafts skip draw.

[Illustration:  Fig. 25]

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[Page 24] Serge, 4-2, 1-1, 1-1.